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Related papers: Persistent Near-Surface Flow Structures from Local…

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As the amount of asteroseismic data available continues to grow, the inability to accurately model observed oscillation frequencies is becoming a critical problem for interpreting these frequencies. A major component of this problem is the…

Solar and Stellar Astrophysics · Physics 2020-07-01 J. Schou , A. C. Birch

Many helioseismic measurements suffer from substantial systematic errors. A particularly frustrating one is that time-distance measurements suffer from a large center to limb effect which looks very similar to the finite light travel time,…

Solar and Stellar Astrophysics · Physics 2015-06-11 Charles S. Baldner , Jesper Schou

Understanding the magnetic fields of the Sun is essential for unraveling the underlying mechanisms driving solar activity. Integrating topological data analysis techniques into these investigations can provide valuable insights into the…

Solar and Stellar Astrophysics · Physics 2024-01-31 Pablo Santamarina Guerrero , Yukio Katsukawa , Shin Toriumi , David Orozco Suárez

We constrain the velocity spectral distribution of global-scale solar convective cells at depth using techniques of local helioseismology. We calibrate the sensitivity of helioseismic waves to large-scale convective cells in the interior by…

Solar and Stellar Astrophysics · Physics 2015-05-18 S. M. Hanasoge , T. L. Duvall , M. L. DeRosa

We employ time sequences of images observed with a G-band filter (4305{\AA}) by the Solar Optical Telescope (SOT) on board of Hinode spacecraft at different latitude along solar central me-ridian to study vorticity of granular flows in…

Solar and Stellar Astrophysics · Physics 2017-02-02 A. A. Pevtsov

Recently, the characteristics, and dynamics of a persistent 1.7 h vortex flow, resembling a small-scale tornado, have been investigated with ground-base and space-based observations and for the first time in the Ha line centre. The vortex…

Solar and Stellar Astrophysics · Physics 2019-03-13 K. Tziotziou , G. Tsiropoula , I. Kontogiannis

Vortex flows are structures associated with the rotation of the plasma and/or the magnetic field that are present throughout the solar atmosphere. In recent years, their study has become increasingly important, as they are present on a wide…

Solar and Stellar Astrophysics · Physics 2025-04-04 M. Koll Pistarini , E. Khomenko , T. Felipe

The solar cycle onset at mid-latitudes, the slow down of the sunspot drift toward the equator, the tail-like attachment and the overlap of successive cycles at the time of activity minimum are delicate issues in $\alpha\Omega$ dynamo wave…

Solar and Stellar Astrophysics · Physics 2016-09-07 R. Simoniello , S. C. Tripathy , K. Jain , F. Hill

We recently presented evidences (Rajaguru et al. 2012) that seismic halos around expanding magnetic structures in the lower solar atmosphere are related to the acoustic to magnetoacoustic wave conversions, using multi-height data from…

Solar and Stellar Astrophysics · Physics 2013-08-28 S. P. Rajaguru , Xudong Sun , K. Hayashi , S. Couvidat

We analyze the effect of a sunspot in its quiet surroundings applying a helioseismic technique on almost three years of Helioseismic and Magnetic Imager (HMI) observations obtained during solar cycle 24 to further study the sunspot…

Solar and Stellar Astrophysics · Physics 2018-05-23 M. Cristina Rabello-Soares , Richard S. Bogart , Philip H. Scherrer

We present results on variation in rotation rate in the upper convection zone using data from GONG and MDI/SOHO covering a period of more than four years. We find that the first few odd-order splitting coefficients vary systematically with…

Astrophysics · Physics 2007-05-23 Kiran Jain , S. C. Tripathy , A. Bhatnagar

We present an analysis of rotation measure (RM) fluctuations from the Test Region of the Southern Galactic Plane Survey (SGPS), along with emission measure (EM) fluctuations in the same field taken from the Southern H-Alpha Sky Survey…

We report on new spectro-polarimetric measurements with simultaneous filter imaging observation, revealing the frequent appearance of polarization signals indicating high-speed, probably supersonic, downflows that are associated with at…

Many engineering and environmental surfaces exhibit spatial heterogeneity in the spanwise direction and encompass multiple surface length scales. When the dominant spanwise length scale is on the order of the largest flow scales (e.g., the…

Fluid Dynamics · Physics 2025-05-27 Mattias Nilsson-Takeuchi , Bharathram Ganapathisubramani

Using helioseismic holography strong evidence is presented that the phase (or equivalent travel-time) of helioseismic signatures in Dopplergrams within sunspots depend upon the line-of-sight angle in the plane containing the magnetic field…

Solar and Stellar Astrophysics · Physics 2010-02-12 H. Schunker , D. C. Braun , P. S. Cally

The influence of the basic rotation on anisotropic and inhomogeneous turbulence is discussed in the context of differential rotation theory. An improved representation for the original turbulence leads to a $\Lam$-effect which complies with…

Astrophysics · Physics 2009-11-11 L. L. Kitchatinov , G. Rüdiger

Numerical studies performed with a primitive equation model on two-dimensional sinusoidal hills show that the local velocity profiles behave logarithmically to a very good approximation, from a distance from the surface of the order of the…

Chaotic Dynamics · Physics 2009-10-31 S. Besio , A. Mazzino , C. F. Ratto

While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local…

Global hydrodynamic simulations of internal solar dynamics have focused on replicating the conditions for solar-like differential rotation and meridional circulation using the results of helioseismic inversions as a constraint. Inferences…